Key-changing combination-lock



W-. T. BENHAM.

KEY CHANGING COMBINATION LOCK.

APPLICATION FILED APR. Is, 1918.

1,341,876. Patented June 1, 1920.

WILLIAM T. IBENHAM, 0F NORWOOD, OHIO, ASSIGNOR TO. THE MOSLER LOCK COMPANY,

OF CINCINNATI, OHIO, A CORPORATION. OF OHIO Specification of Letters Patent.

Patented June 1, 12920.

Application filed April 18, 1918. Serial No. 229,309.

To all whom it may concern:

Be it known that 1, WILLIAM T. BENHAM, a citizen of the United States, residing at Norwood, in the county of Hamllton and State "of Ohio, have invented new and useful Improvements in Key-Chang1ng Combination-Locks, of which the following is a specification. I

My invention relates to key-changing combination or tumbler locks, its object 'being to improve the efficiency of said locks herewith, a combination lock adapted to use on a street-door, closet or similar uses.

In these draw1ngs Figure 1 1s a partlal sectlon 1n the axial plane of the arbor, of a portion of a complete lock detached, showing the tumblers, the rotating arbor, and the drive wheel; and showing the new key-seating element and the key in place in its relation to the lock case, tumblers and drive wheel;

Fig. 2 is a plan view of the lock case showing the cover removed.

Fig. 3 is a plan view of the inner face of the cover of the lock case showing in dotted lines the tumblers and adjuncts.

Figs. 4, 5 and 6 are a detail plan, an elevation and an under plan, respectively, of the key-seating element; and

Fig. 7 is an elevation of the front part of.

the bolt, showing the contact spring in position (sectioned).

Referring to the drawings, A designates the lock case, and A its cover plate. The usual two-part tumblers, a a of, are carried upon a hollow stud, a, depending from the underside of the cover plate A The drive wheel, B, of the system is carried upon the squared portion of an arbor, I), inserted through the bottom plate of the lock casing and extending upward through the axial aperture of the stud at The usual contact pin, 10, upon the drive wheel when rotated contacts with a corresponding pin, 29, upon the near face of the adjacent tumbler, a and similar pins upon the other tumblers transmit rotative motion from the arbor, 6, through the series of tumblers for setting or changing combinations. Rotation of the arbor, b, iseifected by an external knob, B and the usual dial plate, B determines the stopping places. All these being common and well understood, require no further description. T

In locks of this description, as heretofore constructed, the setting key, a, employed in releasing the dog or brake connections (not shown), between the outer and inner concentric elements of the tumblers, is passed downward through the tumbler series, and has its seats and hearings in and through the opposite side plates of the lock casing. This renders it necessary to employ a drive wheel of reduced diameter in order to avoid contact with the key. The disadvantage of a relatively small drive wheel is .well known. Not only is a longer contact arm of the angle-bar made necessary (which reduces the throw of the bolt), but it must extend inward between the casing and drive wheel and is liable to frictional interference. The excess of curvature and limitation of contact space at the periphery ofthe drive wheel also requires greater care and accuracy of fitting parts and all these impair certainty of action,

In my improvement, these difficulties are avoided. and a drive wheel as large or larger than the tumblers may be employed.

To this end, I have devised a key seat and guide formed in a boss, C, attached to the outer face of the. cover plate, A The boss, shown in detail in Figs. 4, 5 and 6, is preferably constructed as a short cylinder having short axial extensions above and below the latter. seating in a corresponding aperture of the cover plate A A circular aperture, 0, extends axially entirely through the boss, having a radial slot, 0 at one side of the aperture, and a radial recess, 0 is cut into the under face of the enlarged midportion of the boss, opening into the central aperture, as shown in Figs. 5 and 6. This recess is proportioned to accommodate a radial fin of the key through a quarter revolution of the latter, presently to be described.

The key, is, and its relation to the tumblers and drive wheel is shown in Fig. 1. It is a round bar squared toward the end, from the point where it enters the tumblers, to engage corresponding apertures, e, in'the cams or Spreaders (Fig. 3). Just above this point is a small radial wing, d, which enters the radial slot 0 of the boss, 0, and prevents rotation of the key until it reaches the level of the recessfc which allows the wing to swing one quarter of a revolution but permits no withdrawal until returned to its starting point. Thus the key is (1) required to be inserted fully through the tumblers and no further before it can be rotated; (2) must be returned to original radial position of entrance before it can be Withdrawn,thus insuring against forgetfulness or carelessness on the part of the operator.

A further improvement consists in the construction and arrangement of the angle bar, spring and bolt, whereby a single spring acts upon the angle bar and bolt in a mode insuring the proper action of both.

The relations of the drive wheel, B, angle bar, E, and bolt, F, are clearly shown in Fig. 2. A spring, 8, is provided, secured to the angle bar, E, as shown, and curved around its rear and forward to a contact with a rear shoulder of the bolt, F, as shownin-Figs. 2 and 7. In the positions shown, the short arm, 6 of the angle bar is held by the spring, 8, in contact with the curved periphery of the drivewheel B, while the spring also bears outwardly upon the bolt to keep it extruded. The extended finger e of the angle bar E, however, is somewhat removed from contact with the receding lug, 7, of the bolt F, so that, when the drive wheel, B, is rotated to bring the slot 5 in line with the short arm, 6 of the angle bar, the first action of the spring is wholly directed to seating the short arm in said slot and the further rotationof the ,drive wheel rotates the angle bar and withdraws the bolt by the action of the finger, 6 ,The usual dog, 9, is provided, which, by means of an arbor and knob (not shown),.,is rotated to recede the bolt independently of the angle bar.

Thus all the advantages of the ordinary spring night latch are realized in a tumbler lock, and the single spring answers the purpose of two, with better advantage. lVhen it is desired to hold the night latch out of use, the dog, g, is turned back to a dead center engagement against the bolt, Which is then held in receded position until the dog is released, whereupon the spring 8, throws it outward.

Where the lock is mortised in a door, the key seat 0 may be detached to seat the lock case in the mortise and be subsequently applied through a corresponding aperture as indicated in Fig. 5, in which the portion of the door concerned is indicated in section at m, and secured by screws, y.

The form and proportions of the keyseating boss 0 are those of convenience merely, and may be varied. The lower extension, for example, is convenient for a perfeet and permanent alinement of the device in relation to the casing and tumblers. The

upper extension forms a neat finish as avisible key hole. The essential thing is suflicient length to form a perfect bearing and hold the key in line for its Work, guide it non-rotatively to its position for proper action and limit the same.

I claim as my invention and desire to secure by Letters Patent of the United States A key seating and guide device for use by attachment exteriorly to a tumbler lock, said device having a relatively long circular aperture adapted to receive and constitute an exclusive guide and bearing for a correspondingly formed key shank; and provided also with correspondingly elongated slot or key seat opening into said aperture, and adapted to receive a radial wing upon the key shank, only to the proper depth of key insertion for actuating all the tumblers, and further provided with a lateral cavity of depth and form to admit the wing of the key when in actuating position to swing through a quarter circle only and prevent linear movement of the key until returned to initial radial position.

In testimony whereof I have hereunto set my hand in presence of two subscribing Witnesses.

WILLIAM BENHAM.

Witnesses i WALTER A. KNIGHT, CARL PHARES. 

